Environmental samples taken at the shop’s warehouse, where other species of small animals are held, also confirmed traces of coronavirus, officials said. The hamsters at the pet store were imported from the Netherlands in two batches — on December 22 and January 7.

On Tuesday, authorities seized all the small animals in the shop, including hamsters, rabbits, guinea pigs and chinchillas, to be tested and euthanized — regardless of the test result — citing a health hazard to the public.

All pet stores selling hamsters in the city have been ordered to hand the animals over to be put down, with similar orders for anybody who bought a hamster in the lead-up to Christmas, beginning December 22.

Photos on Tuesday night show Covid control workers in hazmat suits at numerous pet stores, disinfecting the premises and bringing out bulky red plastic bags.

All animals taken from the store would be dealt with “humanely,” authorities said.

Authorities also suspended the import of all small animals into the city, and told all pet stores selling hamsters to suspend operations immediately until all their small animals have tested negative. Officials urged residents on Tuesday to “adopt good hygiene practices” with their pets, including avoiding kissing them.

More than 20,000 people have signed the largest online petition urging the government not to cull the animals. Some social media users said many hamsters may have been bought around the holidays as gifts for young children.

“Hamsters are our family, everybody please think rationally, don’t give them up because of one incident,” said the Hamster Concern Society, a volunteer organization in Hong Kong.

Hong Kong’s Society for the Prevention of Cruelty to Animals (SPCA) said in a statement it was “shocked and concerned” by the government’s decision, which “did not take animal welfare and human-animal bond into consideration.”

In a Facebook post on Wednesday, the hamster concern group said it had been flooded with questions and pleas from anxious pet owners. “My household’s hamster wasn’t bought from a pet store, but my family is very worried and want me to send it away,” said one owner, according to the group. “But I don’t want to, is there any way to test my hamster?

According to the US Centers for Disease Control and Prevention, there have been documented Covid-19 cases in animals who likely caught the virus from humans — however, there is far less evidence to suggest the possibility of animal-to-human transmission.

But authorities defended the cull, arguing it was in the interest of public health and safety.

Hong Kong has stuck to a strict zero-Covid approach, aiming to stamp out all cases internally while maintaining strict border controls, even as increasingly transmissible variants — first Delta and now Omicron — make that more and more difficult.

Hong Kong is one of the few places still adhering to that strategy, in the hopes of reopening its border with mainland China, which continues to lock down millions of residents in an attempt to eradicate Covid.

A spokesperson for the city’s Agriculture, Fisheries and Conservation Department (AFCD) said Tuesday that all hamsters would be killed regardless of their test result because the virus’ incubation period means “negative test results do not necessarily mean that the hamsters have not been infected.”

He added that the government doesn’t have the facilities or means to test more than a thousand hamsters every day, let alone isolating and quarantining all the small animals in the city — so killing them was “a safe and feasible way to control the epidemic.”

Testing and isolating pets, and killing only the ones determined to be a threat, “could not control the epidemic completely and may cause loopholes,” he added.

Mainland China has also taken similar measures against pets during the pandemic.

Both cases went viral on Chinese social media, sparking widespread dismay and anger among pet owners and sympathizers — though some posters argued human lives were more important to protect than those of animals.

The Hong Kong AFCD spokesperson also pointed to European countries like the Netherlands and Denmark that had conducted similar mass cullings over Covid transmission concerns.

In November 2020, Denmark said it found a mutated strain of the coronavirus among its mink population that had spread to humans. In response, the government announced the culling of 17 million mink to stop its spread.

Denmark’s parliament commissioned an inquiry into whether ministers had known that the legal framework was absent, with the investigation set to finish in April.